As we know ever the biggest sites have duplicate content and SEO problems (See the BBC duplicate content post). I’ve come across another site site with a duplicate content problem today, Facebook.
With the recent change to get a URL with your name in it also seems that my profile can also appear on another domain.
At the moment the en-gb.facebook URL isn’t indexed in Google but there are other people’s profiles indexed. Twitter also have a duplicate content issue with indexing on the secure https server.
Wonder if they’ll start to 301 to the other? I’ve seen a number of Google results with both URL’s listed.